TO STUDY BIOREMEDIATION AND TOXICITY OF LEAD AND ARSENIC THROUGH ENTOMOPATHOGENIC AND ANTAGONISTIC FUNGI

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2018-11
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UHF, NAUNI
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ABSTRACT The present investigations entitled “To study bioremediation and toxicity of Lead and Arsenic through entomopathogenic and antagonistic fungi” was conducted during 2017-2018 in the Department of Environmental Science, College of Forestry, Dr. Y.S. Parmar University of Horticulture and Forestry, Nauni Solan H.P. The study comprised of 4 fungal strains viz. Beauveria bassiana and Metarhizium anisopliae (entomopathogenic fungi) and Aspergillus niger and Trichoderma harzianum (antagonistic fungi) which were tested for their toxicity and bioremediation for lead and arsenic (heavy metals). The cultures of these fungi were maintained under laboratory conditions in the B.O.D incubator at 25±10C. The effect of different doses of lead and arsenic on various fungal parameters such as radial growth, per cent growth inhibition, mycelium dry weight, germination of spores and reduction potential of fungi and heavy metal uptake by fungal mycelia was studied. The whole experiment was replicated thrice in CRD. Significantly maximum mean radial growth (0.98 mmh-1) was observed in A. niger at 0 ppm for Pb while it was 0.73 mmh-1 for As in T. harzianum at 0 ppm. The mean radial growth decreased with increase in concentrations of Pb and As from 0 to 10 ppm. At 10 ppm concentration M. anisopliae showed maximum per cent growth inhibition of 50.96 per cent and 73.33 per cent for Pb and As, respectively. With increase in concentration of Pb and As per cent growth inhibition also increased for each fungi. The dry weight of A. niger and T. harzianum was higher than other fungi i.e. 283.33 mg and 240.00 mg for Pb and As respectively at 0 ppm concentration. Mycelium dry weight decreased with increase in concentration of both the heavy metals. Spore germination percentage and reduction potential for all the fungi under two doses (1×103 spores/ml and 1×105spores/ml) was recorded against both the heavy metals (Pb and As). In all the fungi per cent spore germination decreased with increase in the concentration of Pb and As while reduction potential increased with increase in concentration of Pb and As, respectively from 0 to 10 ppm. The spore germination percentage in the presence of Pb and As was in the order of T. harzianum > A. niger > M. anisopliae > B. bassiana. Maximum Pb uptake was recorded for B. bassiana at 10 ppm (0.30 mg/g). The order of fungi with respect to Pb uptake was B. bassiana > T. harzianum > A. niger > M. anisopliae. Maximum As uptake was recorded for T. harzianum at 10 ppm (0.324 mg/g). The order of fungi with respect to As uptake was T. harzianum > A. niger > B. bassiana > M. anisopliae. From the study it can be concluded that though the entomopathogenic fungus B. bassiana had low radial growth, high per cent growth inhibition and low spore germination at 10 ppm concentration of Pb but it had maximum Pb uptake among all the fungi and could be used for remediation of low levels of Pb (<10 ppm). Whereas, antagonistic fungus T. harzianum had highest radial growth, lowest per cent growth inhibition, highest spore germination and maximum uptake of As and could be used in remediation of low As (<10 ppm). The present studies also widens the scope for studying the effect of higher concentrations of heavy metals in future to confirm the survival and bioremediation ability of these fungi.
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